Why do we do what we do? Behave is at once a dazzling tour and a majestic synthesis of the whole science of human behaviour. Brought to life through simple language, engaging stories and irreverent wit, it offers the fullest picture yet of the origins of tribalism and xenophobia, hierarchy and competition, morality and free will, war and peace. Robert Sapolsky's ingenious method is to move backwards in time from the moment at which a behaviour occurs, layer by layer through the myriad influences that led to it: - We begin with the split-second reactions of the brain and nervous system...Then we consider our response to sight, sound and smell in the minutes and seconds beforehand...Next he explains the interactions of hormones, which prime our behaviour in the preceding hours and days...He proceeds through the experiences of adolescence, childhood and foetal development that shape us over our lifespans...And continues over centuries and millennia through the profound influences of genetic inheritance, cultural context and ultimately the evolutionary origins of our species.